Field of the Invention
This document relates to a multi-view autostereoscopic image display and a method of controlling an optimal viewing distance thereof.
Discussion of the Related Art
As the stereoscopic image reproduction technology is applied to display devices, such as a television or a monitor, now is the age in which people can view 3D stereoscopic images even at home. A stereoscopic image display can be divided into a glasses type and an autostereoscopic type. The glasses type display can display left and right parallax images on a direct-view display or projector by changing polarization direction thereof or by a time-divisional manner, and implement a stereoscopic image using polarization glasses or liquid-crystal shutter glasses. In the autostereoscopic type, optical elements can be installed in front of or behind a display screen. The optical elements can include a parallax barrier for separating the optical axes of left and right parallax images, and a lenticular lens (hereinafter “lens”).
In the autostereoscopic image display, as shown in FIG. 1, an optimal viewing distance OVD from which a viewer can properly view a stereoscopic image is calculated based on the back length between a pixel array PIX of a display panel and a lens LENS, the focal length of the lens LENS, a pixel pitch Ppix, a lens pitch Plens, and the distance between the left and right eyes of the viewer. In FIG. 1, the back length, the focal length of the lens LENS, the pixel pitch Ppix, the lens pitch Plens, and the distance between the left and right eyes of the viewer is fixed to constant values. The distance between the left and right eyes of the viewer is 65 mm for average adults. Therefore, the optimal viewing distance OVD for the autostereoscopic image display is fixed to a specific position, as shown in FIG. 1. Even when the autostereoscopic image display has a barrier, instead of the lens of FIG. 1, the optimal viewing distance OVD is fixed to a specific position.
In FIG. 1, “REZ” denotes a right-eye viewing zone where pixels with a right-eye image written therein (hereinafter, “right-eye pixels”) R can be seen, and “LEZ” denotes a left-eye viewing zone where pixels with a left-eye image written therein (hereinafter, “left-eye pixels”) L can be seen. “PSUBS” is a transparent substrate for securing the back length between the pixel array PIX and the lens LENS.
If the viewer moves forward or backward from the optimal viewing distance OVD, one eye (right eye or left eye) of the viewer sees both the left-eye pixels and the right-eye pixels, making the viewer feel 3D crosstalk. The autostereoscopic image display can be implemented as a multi-view system. In the multi-view system, a multi-view image is written in the pixel array PIX to enable the viewer to see a stereoscopic image at different positions from the optimal viewing distance OVD. In such a multi-view system, if the viewer moves forward or backward from the optimal viewing distance OVD, view images seen through one eye of the viewer are doubled, thus making the viewer feel 3D crosstalk.